我的代码中有奇怪的段错误

Question

对于我的代码，我必须在C中读取两个文件，将这两个文件的内容解释为矩阵，然后添加或乘以矩阵并将结果打印到屏幕上。给定的只是操作和两个输入文件，矩阵的维度是未知的。我有一些奇怪的段错误代码行似乎符合这些函数的用法。你看看吗？感谢。

这是代码：

#include <stdio.h>
#include <stdlib.h>

void matrixadd (long **mat1, long **mat2, int rows, int cols) {
    int i, j;
    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++) {
            printf("[%d][%d]: %ld ", i, j, mat1[i][j] + mat2[i][j]);
        }
        printf("\n");
    }
}

void matrixmult (long **mat1, long **mat2, int * dim1, int * dim2) {
    int i, j, k;
    long curnum;
    for (i = 0; i < dim1[0]; i++) {
        for (j = 0; j < dim2[1]; j++) {
            curnum = 0;
            for (k = 0; i < dim1[1]; k++) {
                curnum += mat1[i][k]*mat2[k][j];
            }
            printf("[%d][%d]: %ld", i, j, curnum);
        }
        printf("\n");
    }
}

int filetomat (FILE *file, long **mat, int * dim) {
    int rows = 0, cols = 0;
    long fac = 1l;
    long curnum = 0;
    char c;
    int n_spaces = 0;
    while ((c = fgetc(file)) != EOF) {
        if (c == '-') {
            fac = -1l;
        }
        if (c >= '0' && c <= '9') {
            curnum *= 10;
            curnum += (int)(c-'0');
        }
        if (c == ' ') {
            mat[0][n_spaces] = fac*curnum;
            n_spaces++;
            fac = 1;
            curnum = 0;
            mat[0] = (long *)realloc(mat[0], sizeof(long)*(n_spaces+1));
            if (mat[0] == NULL) {
                printf("Allocation error.");
                return 1;
            }
        }
        if (c == '\n') { // Füge letzte Zahl in Matrix ein
            mat[0][n_spaces] = fac*curnum;
            fac = 1l;
            curnum = 0;
            rows++;
            cols = n_spaces;
            mat = realloc(mat, 2*sizeof(long *));
            if (mat == NULL) {
                printf("Allocation error.");
                return 1;
            }
            n_spaces = 0;
            break;
        }
    }
    mat[1] = calloc(cols+1, sizeof(long));
    if (mat[1] == NULL) {
        printf("Allocation error");
        return 1;
    }
    while ((c = fgetc(file)) != EOF) {
        if (c == '-') {
            fac = -1l;
        }
        if (c >= '0' && c <= '9') {
            curnum *= 10;
            curnum = (int)(c-'0');
        }
        if (c == ' ') {
            if (n_spaces > cols) {
                printf("n_spaces %d > cols %d, row %d\n", n_spaces, cols, rows);
                return 1;
            }
            mat[rows][n_spaces] = fac*curnum;
            n_spaces++;
            fac = 1;
            curnum = 0;
        }
        if (c == '\n') {
            if (n_spaces != cols) {
                printf("n_spaces %d != cols %d, row %d\n", n_spaces, cols, rows);
                return 1;
            }
            mat[rows][n_spaces] = fac*curnum;
            fac = 1l;
            curnum = 0;
            rows++;
            n_spaces = 0;
            mat = realloc(mat, sizeof(long *)*(rows+1));
            mat[rows] = (long *)calloc(cols+1, sizeof(long));
            if (mat == NULL || mat[rows] == NULL) {
                printf("Allocation error");
            }
        }
    }
    dim[0] = rows-1;
    dim[1] = cols;
    return 0;
}

int main (int argc, char **argv) {
    if (argc < 4) {
        printf("Not enough arguments");
        return 1;
    }
    int stat1, stat2;
    FILE *f1, *f2;
    long **mat1, **mat2;
    int *dim1 = (int *)calloc(2, sizeof(int));
    int *dim2 = (int *)calloc(2, sizeof(int));
    if (dim1 == NULL || dim2 == NULL) {
        printf("Allocation error");
        return 1;
    }
    mat1 = calloc(1, sizeof(long *));
    mat1[0] = (long *)malloc(sizeof(long));
    mat2 = calloc(1, sizeof(long *));
    mat2[0] = (long *)malloc(sizeof(long));
    if (mat1 == NULL || mat1[0] == NULL || mat2 == NULL || mat2[0] == NULL) {
        printf("Allocation error");
    }
    char op;
    if (argv[1][0] == '+' || argv[1][0] == 'x') {
        op = argv[1][0];
    }
    else {
        printf("Unknown operation");
        return 1;
    }
    f1 = fopen(argv[2], "r");
    f2 = fopen(argv[3], "r");
    stat1 = filetomat(f1, mat1, dim1);
    stat2 = filetomat(f2, mat2, dim2);
    fclose(f1);
    fclose(f2);
    if (stat1 > 0 || stat2 > 0) {
        printf("Matrices not valid.");
        return 1;
    }
    if (dim1[1] == dim2[0] && op == 'x') {
        matrixmult(mat1, mat2, dim1, dim2);
    }
    else if (dim1[0] == dim2[0] && dim1[1] == dim2[1] && op == '+' ) {
        matrixadd(mat1, mat2, dim1[0]+1, dim2[0]+1);
    }
    else {
        printf("Operation not defined.");
        return 1;
    }
    return 0;
}

这是输入文件内容的示例：

710562522 1048607709 -380295227
-585472920 -710044615 -44110201
-1057241338 598692442 291232156